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Publication Abstract from PubMed

Segment 5, open reading frame (ORF) 1 of the infectious salmon anemia virus (ISAV) genome encodes for the ISAV F protein, which is responsible for viral-host endosomal membrane fusion during a productive ISAV infection. The entry machinery of ISAV is comprised of a complex of the ISAV F and ISAV HE proteins in an unknown stoichiometry prior to receptor engagement by ISAV HE. Following binding of the receptor to ISAV HE, dissociation of the ISAV F protein from HE and subsequent endocytosis, the ISAV F protein resolves into a fusion competent oligomeric state. Here, we present a 2.1 A crystal structure of the fusion core of the ISAV F protein solved at low pH. This structure has allowed us to unambiguously demonstrate that the ISAV entry machinery exhibits typical Class I viral fusion protein architecture. Furthermore, we have determined stabilizing factors that accommodate the pH-dependent mode of ISAV transmission and our structure has allowed the identification of a central coil that is conserved across numerous and varied post-fusion viral glycoprotein structures. We then discuss a mechanistic model of ISAV fusion that parallels the paramyxoviral Class I fusion strategy wherein attachment and fusion are relegated to separate proteins in a similar fashion to ISAV fusion.

Electrostatic Architecture of the Infectious Salmon Anemia Virus (ISAV) Core Fusion Protein Illustrates a Carboxyl-Carboxylate pH-Sensor.,Cook JD, Soto-Montoya H, Korpela MK, Lee JE J Biol Chem. 2015 Jun 16. pii: jbc.M115.644781. PMID:26082488^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.